- Default serving240 mlTea
- Counts toward goal240 mlhydration factor 1.00
- Caffeine30 mgper 240 ml serving
- Calories2 kcal1 kcal per 100 ml
Move the slider to see what a bigger or smaller green tea does to the numbers. The app uses the same figures. The caffeine comes from the shot count, not from the volume, so it stays put as you drag.
See when today's caffeine clears with the caffeine cutoff calculator.
It counts, all of it
A 240 ml cup of green tea adds 240 ml to the goal. Its hydration factor is 1.00, identical to water, and that is not a courtesy. Researchers measured how much of a range of everyday drinks the body retained. Tea sat in the same group as still water. The trial is cited at the foot of this page. Tea is water with a small amount of caffeine and a trace of dissolved leaf in it. And 30 mg is nowhere near the dose where the mild diuretic effect starts to matter.
A third of a coffee's caffeine
Thirty milligrams is about a third of what a 240 ml cup of black coffee delivers and under half an espresso shot. Four cups spread across a day come to 120 mg, barely more than one cup of black coffee on its own. This is why green tea works as the afternoon drink when the caffeine budget has run out. The app's coffee deadline may have closed hours ago. A cup of green tea will often still fit under it.
The strength of your cup is a brewing decision
Green tea is unusual in how much the number depends on you rather than on the leaf. Water temperature and steep time move the caffeine more than the quantity of leaf does. One minute at 70 °C pulls out far less than three minutes at 90 °C from the same spoonful. The 30 mg here is a middle-of-the-road cup. Yours may be reliably stronger or weaker, say a long-steeped sencha or a genmaicha cut with rice. If so, save a custom drink in the app with your own caffeine figure. Anything decaffeinated gets logged with the Caffeine-free switch.
Hydration factors follow the Beverage Hydration Index: Maughan RJ, Watson P, Cordery PA, et al. “A randomized trial to assess the potential of different beverages to affect hydration status: development of a beverage hydration index.” American Journal of Clinical Nutrition, 2016;103(3):717-723. Read the paper on PubMed. In WaterChamp a green tea counts the same as plain water.
